Main left coronary artery disease. Clinical experience from 1964-1974.

Obstructive lesions of the main left coronary artery (LCA) were demonstrated angiographically in 73 patients, comprising 4.3% of the total population referred to us for diagnostic evaluation of chest pain. Although there were no specific historical or clinical features which could absolutely distinguish this subgroup from the larger population of coronary artery disease patients, 81% (34/42) of the double Master's exercise tests, in which the patient achieved a heart rate of at least 110 beats/min. demonstrated greater than or equal 2 mm R-ST segmental depression. Of the total group of 73, 32 were evaluated during the six-year period from 1964 to 1971 and a preliminary report made in 1972. The diagnosis in the remaining 41 patients was established in the 1/2 year period from 1971 to 1973. The initial 32 patients were seen before the significance of a main LCA lesion was appreciated. In this subgroup there were five deaths at the time of cardiac catheterization. However, in the more recent group improved recognition of patients with possible main LCA disease prior to catheterization has led to a much lower death rate related to diagnostic catheterization. Only one of the last 41 patients undergoing coronary angiography has died. Nineteen patients were managed medically. Of this group 17 were considered to be under the same risk of death as the surgical candidates. Their mortality rate, as high. The risk of hying was 43.6% after 24 months, 51.1% after 36 months, and 73.6% after 42 months of observation. Although the initial surgical experience, using internal mammary artery implants and saphenous venin bypass grafts, was associated with a high mortality, direct revascularization surgery over the last 2 1/2 years has been accomplished with a perioperative mortality of only 6.2%. All deaths in the group of 40 patients receiving elective revasularization with saphenous vein bypass grafts occurred in the first six months following surgery. The risk of dying was 12.5% after six months of observation and was unchanged for the remainder of the follow-up period. After 21 months the difference in survival between the two groups is statistically significant (P less than 0.05). The one late death among the surgical survivors occurred four months after the operative procedure and was related to noncardiovaxcular surgical complications. The surgical survivors have been followed for an average of 27 months. Thus revascularization surgery has improved the prognosis for patients with main LCA disease. We currently advise prompt evaluation for any patient suspected of having this type of obstruction and urgent idrect revascularization surgery if this lesion is demonstrated angiographically.